Overview:
For security reasons, transport data is often encrypted and encoded in the transmission of the network, which involves the following:
1, MD5 encryption, the encryption algorithm is one-way encryption, that is, the encrypted data can no longer be restored by decryption. The related classes are included in the Java.security.MessageDigest package.
2, 3-des encryption, the encryption algorithm is reversible, the decryption party can be encrypted by the agreement with the secret key to decrypt. The related classes are included in the javax.crypto.* package.
3. Base64 encoding is the most commonly used encoding method for transmitting 8bit byte code. Related classes are in Sun.misc.BASE64Decoder and Sun.misc.BASE64Encoder.
4, Urlencoder code, is a character encoding, to ensure that the parameters are transmitted by following the specification of the text composition. The related class is in the Java.net.URLEncoder package.
Details:
1, to carry out MD5 encryption, get byte[]/** * MD5 encryption * @param String of the original Spkey * @return byte[] Specify the encryption mode MD5 after byte[]/private byte[] MD5 (string STRSRC) {byte[] returnbyte = null; try {messagedigest MD5 = messagedigest.getinstance ("MD5"); returnbyte = Md5.digest (s Trsrc.getbytes ("GBK")); catch (Exception e) {e.printstacktrace ();} return returnbyte; 2, Get 3-des key/** * Get the 3-des key * According to the need, such as the secret key is 24 bytes, MD5 encryption is 16 bytes, so after 8 bytes of 0 * @param String original Spkey * @return byte[] Specifies that the encryption method is MD5 byte[]/private byte[] Getenkey (String spkey) {byte[] deskey=null; try {byte[] desKey1 = MD5 (spkey); DesK EY = new BYTE[24]; int i = 0; while (I < deskey1.length && I <) {Deskey[i] = Deskey1[i]; i++} if (I <) {Deskey[i] = 0; i++;} catch (Exception e) {e.printstacktrace ();} return deskey; } 3, 3-des encryption/** * 3-des encryption * @param byte[] src to 3-des encrypted byte[] * @param byte[] enkey 3-des encryption key * @return byte[] 3-des encrypted byte[] */public byte[] Encrypt (byte[] src,byte[] enkey) {byte[] EncryptedData = null;try {desedekeyspec DKs = new Desedekeyspec (Enkey); Secretkeyfactory keyfactory = secretkeyfactory.getinstance ("Desede"); Secretkey key = Keyfactory.generatesecret (DKS); Cipher Cipher = cipher.getinstance ("Desede"); Cipher.init (Cipher.encrypt_mode, key); EncryptedData = cipher.dofinal (src); catch (Exception e) {e.printstacktrace ();} return EncryptedData; 4. BASE64 Encoding of Strings/** * BASE64 encoding of Strings * @param byte[] src the character to encode * * * @return string to encode the strings/public string getbase 64Encode (byte[] src) {String requestvalue= ""; try{base64encoder base64en = new Base64encoder (); requestvalue=base64en.e Ncode (SRC); System.out.println (Requestvalue); catch (Exception e) {e.printstacktrace ();} return requestvalue; 5, according to the need to remove the string of newline symbol/** * Remove the string line symbol * Base64 encoded 3-des data, the resulting string has a newline symbol, as required can be removed * * * private string filter (String str) {Stri NG output = null; StringBuffer sb = new StringBuffer (); for (int i = 0; i < str.length (); i++) {int ASC = Str.charat (i); if (ASC!= && ASC!=) SB. Append (Str.subsequence (i, i + 1)); Output = new String (SB); return output; 6. Urldecoder.encode (strencoding) Encoding of Strings/** * Urldecoder.encode (strencoding) Encoding of strings * @param string src strings to encode * * String encoded by @return String */public string Geturlencode (string src) {string requestvalue= ""; try{Requestvalue = Urlencod Er.encode (SRC); catch (Exception e) {e.printstacktrace ();} return requestvalue; 7. Urldecoder.decode (strencoding) Decoding of Strings/** * Urldecoder.decode (strencoding) Decoding of Strings * @param string src strings to be decoded * * The string that is decoded @return String */public string Geturldecoderdecode (string src) {string requestvalue= ""; try{Requestvalue = U Rldecoder.decode (SRC); catch (Exception e) {e.printstacktrace ();} return requestvalue; 8, carry out 3-des decryption (the key is equivalent to the encryption key)/** * * for 3-des decryption (the secret key is equivalent to the encryption key). * @param byte[] src to be 3-des decrypted byte[] * @param string Spkey Allocated Spkey * @return string 3-des decrypted string/public string decry PT (byte[] debase64,string spkey) {String strde = null; Cipher Cipher = null; try { Cipher=cipher.getinstance ("Desede"); byte[] key = Getenkey (Spkey); Desedekeyspec DKs = new Desedekeyspec (key); Secretkeyfactory keyfactory = secretkeyfactory.getinstance ("Desede"); Secretkey SKey = Keyfactory.generatesecret (DKS); Cipher.init (Cipher.decrypt_mode, SKey); byte ciphertext[] = cipher.dofinal (debase64); Strde = new String (ciphertext, "utf-16le"); catch (Exception ex) {Strde = ""; Ex.printstacktrace (); return Strde; After the above steps can be completed MD5 encryption, 3-des encryption, base64 encoding transmission, base64 decoding, 3-des decryption get the original text. The full text of the procedure is as follows: Package com.neusoft.test.util.crypt; Import java.io.IOException; Import java.io.UnsupportedEncodingException; Import Java.net.URLDecoder; Import Java.net.URLEncoder; Import Java.security.MessageDigest; Import Java.text.SimpleDateFormat; Import Java.util.Calendar; Import Javax.crypto.Cipher; Import Javax.crypto.SecretKey; Import Javax.crypto.SecretKeyFactory; Import Javax.crypto.spec.DESedeKeySpec; Import Sun.misc.BASE64Decoder; Import Sun.misc.BASE64Encoder; /** * <p>title: Encryption and decryption Test </p> * * <p>description: Encryption and Decryption </p> * *<p>date:2005-08-11</p> * * <p>copyright:copyright (c) 20 neusoft</p> * * <p>Company:neusoft</p> * * * @author MENGK * @version 1.00 * * <p>--------------(* * * * * * * * * ----------------------------------------------</p> * <p> modification History </p> * <p> serial number date modification reason </p > * <p> 1 </p>/public class Endecrypt {/** * MD5 encryption * @param String Original Spkey * @return byte[] Specify the encryption method as M D5 byte[] * * Private byte[] MD5 (String strsrc) {byte[] returnbyte = null; try {messagedigest = MD5 Tance ("MD5"); Returnbyte = Md5.digest (Strsrc.getbytes ("GBK")); catch (Exception e) {e.printstacktrace ();} return returnbyte; /** * Get 3-des Key * According to the interface specification, the secret key is 24 bytes, the MD5 is 16 bytes encrypted, so the 0 * @param String of 8 bytes is followed by the original Spkey * @return byte[] Specifies the encryption method is MD5 by te[] */private byte[] Getenkey (String spkey) {byte[] deskey=null; try {byte[] desKey1 = MD5 (spkey); deskey = new byte[2 4]; int i = 0; while (i < deskey1.length && I <) {Deskey[i] = Deskey1[i]; i++} if (I <) {Deskey[i] = 0; i++;}} catch (Exception e) {e.printstacktrace ();} return deskey; }/** * 3-des encryption * @param byte[] src 3-des encrypted byte[] * @param byte[] enkey 3-des encryption key * @return byte[] 3-des encrypted byte[] * * * Public byte[] Encrypt (byte[] src,byte[] enkey) {byte[] EncryptedData = null; try {desedekeyspec dks = new Desedekeyspec ( Enkey); Secretkeyfactory keyfactory = secretkeyfactory.getinstance ("Desede"); Secretkey key = Keyfactory.generatesecret (DKS); Cipher Cipher = cipher.getinstance ("Desede"); Cipher.init (Cipher.encrypt_mode, key); EncryptedData = cipher.dofinal (src); catch (Exception e) {e.printstacktrace ();} return EncryptedData; /** * BASE64 Encoding of Strings * @param byte[] SRC character * * encoded by @return string/public string Getbase64encode (byte[] s RC) {String requestvalue= ""; try{base64encoder base64en = new Base64encoder (); Requestvalue=base64en.encode (SRC);//Sys Tem.out.println (requesTValue); catch (Exception e) {e.printstacktrace ();} return requestvalue; /** * Remove string newline symbol * Base64 encoded 3-des data, the resulting string has a newline symbol *, must be removed, otherwise uni-wise platform resolution stub will not succeed, * prompts "SP authentication failed." In the process of development, because this problem let me at a loss, * A friend told me to ask Unicom to want a piece of encrypted text, and then to compare with their own generated strings, * This is a good debugging method. My last comparison found that the only difference between the strings I generated was the number of newline. * I also wrote a stub request in C # language, and I didn't find this problem. * */private string filter (String str) {string output = null; StringBuffer sb = new StringBuffer (); for (int i = 0; i < str.length (); i++) {int ASC = Str.charat (i); if (ASC!= && ASC!=) sb.append (str.subse Quence (i, i + 1)); Output = new String (SB); return output; /** * Urldecoder.encode (strencoding) Encoding of strings * @param string SRC strings to be encoded * * @return string encoded strings/public string Geturlencode (string src) {string requestvalue= ""; try{requestvalue = Urlencoder.encode (src);} catch (Exception e) {E.PR Intstacktrace (); return requestvalue; /** * 3-des Encryption * @param string src to be 3-des encrypted String * @param string Spkey Allocated Spkey * @return string 3-des Encrypted String */PU Blic StriNg Get3desencrypt (String src,string spkey) {string requestvalue= ""; try{//3-des secret key byte[] Enkey = Getenkey (Spkey); The content to be 3-des encrypted is in progress/"utf-16le/" byte byte[] src2 = src.getbytes ("Utf-16le"); Bytes byte[] EncryptedData = Encrypt (src2,enkey) for 3-des encrypted content; The contents of 3-des encryption are BASE64 encoded String base64string = Getbase64encode (EncryptedData); BASE64 code to remove line breaks after String Base64encrypt = filter (base64string); The process of escaping the HTML control code in BASE64 encoding Requestvalue=geturlencode (base64encrypt); System.out.println (Requestvalue); catch (Exception e) {e.printstacktrace ();} return requestvalue; /** * Urldecoder.decode (strencoding) Decoding of Strings * @param string src strings to be decoded * * * @return String for decoding strings/public string Geturldecoderdecode (string src) {string requestvalue= ""; try{requestvalue = Urldecoder.decode (src);} catch (Exception E ) {e.printstacktrace ();} return requestvalue; /** * * 3-des decryption (The secret key is equivalent to the encryption key). * @param byte[] src to be 3-des decrypted byte[] * @param string Spkey Allocated Spkey * @return string 3-des decrypted String */PUblic string DeCrypt (byte[] debase64,string spkey) {string strde = null; Cipher Cipher = null; try {cipher=cipher.getinstance ("Desede"); byte[] key = Getenkey (Spkey); Desedekeyspec DKs = new Desedekeyspec (key); Secretkeyfactory keyfactory = secretkeyfactory.getinstance ("Desede"); Secretkey SKey = Keyfactory.generatesecret (DKS); Cipher.init (Cipher.decrypt_mode, SKey); byte ciphertext[] = cipher.dofinal (debase64); Strde = new String (ciphertext, "utf-16le"); catch (Exception ex) {Strde = ""; Ex.printstacktrace (); return Strde; /** * 3-des decryption * @param string src to be 3-des decrypted String * @param string Spkey Allocated Spkey * @return string 3-des Encrypted String */PU Blic string Get3desdecrypt (String src,string spkey) {string requestvalue= ""; try{//Get 3-des key// Urldecoder.decodetml control code to escape the process String Urlvalue=geturldecoderdecode (SRC); The contents of 3-des encryption are BASE64 encoded base64decoder Base64decode = new Base64decoder (); byte[] Base64dvalue = Base64decode.decodebuffer (Urlvalue); The content to be 3-des encrypted is in the/"utf-16le/" byte reQuestvalue = DeCrypt (Base64dvalue,spkey); catch (Exception e) {e.printstacktrace ();} return requestvalue; public static void Main (string[] args) {endecrypt test = new Endecrypt (); String oldstring = "toxin hair"; String Spkey = "1234"; System.out.println ("1"). The assigned Spkey is: "+spkey"; System.out.println ("2"). The content is: "+oldstring); String revalue = Test.get3desencrypt (Oldstring,spkey); Revalue = Revalue.trim (). Intern (); System.out.println ("3-des after the encrypted content:" +revalue); String reValue2 = Test.get3desdecrypt (Revalue,spkey); System.out.println ("3-des decrypted content:" +revalue2);}
